Can you help me with this question? thanks

Classy Shoes made $1 million in profits after taxes last year (which it distributed as dividends) on $5 million in revenue by manufacturing and selling 40,000 pairs of shoes.This year it manufactures the same number of pairs (at the same cost).But its shoes have become "in," which has allowed it to raise the price per pair without reducing unit sales.Which of the following ratios does not change?

a)Leverage

b)ROE

c)Profit margin

d) Turnover

and why?